Die

ABSTRACT

A die includes a stationary die, a movable die, which is opposed to the stationary die and reciprocatable in a first direction to change a distance between the stationary and movable dies, and a transfer mechanism, which transfers a workpiece, upon which plastic deformation work is performed between the stationary and movable dies, in a second direction crossing the first direction. The transfer mechanism includes a clamp portion, which clamps/unclamps the workpiece, a synchronizing member, which is engaged with the movable die to reciprocate in synchronization with reciprocation of the movable die, a clamp-unclamp operation converter, which converts reciprocation of the synchronizing member into clamping/unclamping of the workpiece by the clamp portion, and an advance-return operation converter, which converts reciprocation of the synchronizing member into advance-return operation of the clamp portion, whereby the clamp portion advances the workpiece in the second direction and is returned after advancement of the workpiece.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by referenceJapanese Patent Application No. 2009-142639 filed on Jun. 15, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to a die having a transfer mechanism thattransfers a workpiece upon which plastic deformation work, such as pressworking or forge processing, is performed between a stationary die andmovable die.

2. Description of Related Art:

Conventionally, a transfer press machine that obtains driving force of atransfer device for a workpiece from a power output of a drivingrotatable shaft of the press machine, is known as a transfer pressmachine that performs press work, which is plastic deformation work(see, for example, Japanese Unexamined Patent Application PublicationNo. 2004-337953). In addition, a transfer press machine that obtains thedriving force of the transfer device from an actuator, which is providedseparately from the press machine, is also known (see, for example,Japanese Unexamined Patent Application Publication No. 2005-059080).

However, in the conventional technology of the above-describedPublication No. 2004-337953, a transmission mechanism for transmittingthe output of the rotatable shaft of the press machine to an inputterminal of the transfer device is necessary. Accordingly, the rotatableshaft of the press machine needs to be adapted for the transmission ofthe output. Moreover, a rotational position relationship between anoutput terminal of the rotatable shaft of the press machine and theinput terminal of the transfer device considerably influencessynchronization between press working operation and transferringoperation. Accordingly, work for adjustment of the synchronizationbecomes complicated.

In the conventional technology of the above-described Publication No.2005-059080, the press machine needs to be adapted to include adetecting means for detecting an operating position of the pressmachine, for the synchronization between press working operation andtransferring operation.

As a result of an elaborate investigation into the above-describedproblems, the following method for the synchronization between theworking and transferring operations has been found. That is, if atransfer mechanism that operates in accordance with a displacement stateof a movable die as opposed to a stationary die, is given to a die forperforming plastic deformation work on a workpiece, the workingoperation can be synchronized with the transferring operation withoutthe adaptation of the working machine.

SUMMARY OF THE INVENTION

The present invention addresses at least one of the above disadvantages.

According to the present invention, there is provided a die forperforming plastic deformation work upon a workpiece. The die includinga stationary die, a movable die, and a transfer mechanism. The movabledie is opposed to the stationary die and reciprocatable in a firstdirection to change a distance between the stationary die and themovable die. The transfer mechanism is configured to transfer theworkpiece, upon which plastic deformation work is performed between thestationary die and the movable die, in a second direction that crossesthe first direction. The transfer mechanism includes a clamp portion, asynchronizing member, a clamp-unclamp operation converter, and anadvance-return operation converter. The clamp portion is adapted toclamp or unclamp the workpiece. The synchronizing member is engaged withthe movable die to reciprocate in synchronization with reciprocalmovement of the movable die. The clamp-unclamp operation converter isconfigured to convert reciprocal movement of the synchronizing memberinto clamping and unclamping of the workpiece by the clamp portion. Theadvance-return operation converter is configured to convert thereciprocal movement of the synchronizing member into advance-returnoperation of the clamp portion, whereby the clamp portion advances theworkpiece in the second direction and is returned after advancement ofthe workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features andadvantages thereof, will be best understood from the followingdescription, the appended claims and the accompanying drawings in which:

FIG. 1 is a front view roughly illustrating a structure of a die inaccordance with an embodiment of the invention;

FIG. 2 is a plan view roughly illustrating structures of a lower die anda transfer mechanism of the die;

FIG. 3 is a perspective view illustrating a main feature of the transfermechanism;

FIG. 4 is a front view illustrating the main feature of the transfermechanism;

FIG. 5 is a top view illustrating the main feature of the transfermechanism viewed from an arrow V in FIG. 4;

FIG. 6 is a side view illustrating the main feature of the transfermechanism viewed from an arrow VI in FIG. 4;

FIG. 7 is a timing diagram illustrating an exemplary operation of thedie;

FIG. 8A is a perspective view illustrating an operating state of themain feature of the transfer mechanism that corresponds to time (A) inFIG. 7;

FIG. 8B is a perspective view illustrating an operating state of themain feature of the transfer mechanism that corresponds to time (B) inFIG. 7;

FIG. 8C is a perspective view illustrating an operating state of themain feature of the transfer mechanism that corresponds to time (C) inFIG. 7;

FIG. 8D is a perspective view illustrating an operating state of themain feature of the transfer mechanism that corresponds to time (D) inFIG. 7;

FIG. 8E is a perspective view illustrating an operating state of themain feature of the transfer mechanism that corresponds to time (E) inFIG. 7;

FIG. 9 is a conceptual diagram illustrating power transmission when thedie is used for a press machine; and

FIG. 10 is a conceptual diagram illustrating power transmission when adie in accordance with a comparative example is used for the pressmachine.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the invention is described below with reference to theaccompanying drawings.

As illustrated in FIG. 1, a die 1 includes a lower die 2 disposed on anupper surface of a bolster of a press machine (not shown), and an upperdie 3 disposed on a lower surface of a slide of the press machine. Thelower die 2 may correspond to a stationary die, and the upper die 3 maycorrespond to a movable die. In accordance with the reciprocation of theslide in upper and lower directions or in a vertical direction, theupper die 3 reciprocates in the upper and lower directions to change adistance in a direction in which the upper die 3 is opposed to the lowerdie 2. Plastic deformation work is performed on a workpiece (i.e., apart being worked on) between the lower die 2 and the upper die 3.

The die 1 includes a transfer mechanism 4 that transfers the workpiece,which is plastically deformed between the lower die 2 and the upper die3, rightward in FIG. 1, on the lower die 2. The transfer mechanism 4includes a linear crank mechanism 10 disposed on a leftward portion of aworking stage (plastic deformation working part) in FIG. 1, and aclamping mechanism 20 and a feed mechanism 30 which extend rightwardfrom the linear crank mechanism 10.

As illustrated in FIG. 2, the transfer mechanism 4 is one of a pair oftransfer mechanisms 4, and the mechanisms 4 transfer the workpiece oneafter another to the working stage on the right side, with the workpiececlamped by a pair of holding fingers 40 that are opposed to each other.The holding finger 40 may correspond to a clamp portion. Although inFIG. 2, more than one holding finger 40 (in the present example, eightholding fingers 40), are provided for the transfer mechanism 4, forinstance, in accordance with the number of working stages, aconfiguration and operation of the transfer mechanism 4 will bedescribed below in reference to FIGS. 3 to 9, taking as an example asingle holding finger 40.

As illustrated in FIGS. 3 to 6, the linear crank mechanism 10 extends inthe upper and lower directions, and includes a rod 11 and a crankmechanism 12. An upper end portion of the rod 11 is engaged with theupper die 3 using, for example, a screw or a lock pin, so that the rod11 is reciprocated in the upper and lower directions in synchronizationwith the reciprocation of the upper die 3. The crank mechanism 12 isdisposed on a lower end side of the rod 11 and converts thereciprocation of the rod 11 into rotary movement of a rotatable shaft13. The rod 11 may correspond to a synchronizing member. The clampingmechanism 20 converts the rotary movement of the rotatable shaft 13 intowork clamp-unclamp operation of the holding fingers 40. The feedmechanism 30 converts the rotary movement of the rotatable shaft 13 intoadvance-return operation of the holding fingers 40 in rightward andleftward directions (i.e., in a direction of the rotatable shaft 13) inFIG. 4. The clamping mechanism 20 may correspond to a clamp-unclampoperation converter. The feed mechanism 30 may correspond to anadvance-return operation converter.

The clamping mechanism 20 includes a generally fan-shaped flat plate cam21, a swaying block body 22 as a follower, and a clamp base 24. The flatplate cam 21 is fixed to the rotatable shaft 13 of the crank mechanism12, and rotated in accordance with the rotary movement of the rotatableshaft 13. The swaying block body 22 has a cam follower 22 a that is incontact with an outer peripheral surface of the flat plate cam 21, andis displaced (swayed) in the upper and lower directions in accordancewith the rotary movement of the flat plate cam 21. The holding finger 40is fixed on the clamp base 24.

An inclined groove 22 b (through hole) is formed on the swaying blockbody 22. The inclined groove 22 b is inclined to be further away fromthe holding finger 40 toward an upper portion of the inclined groove 22b in the upper and lower directions. A penetrating bar 23, which extendsin the rightward and leftward directions in FIG. 4 on the opposite sideof the clamp base 24 from the holding finger 40, is provided to passthrough the inclined groove 22 b. The swaying block body 22 issurrounded with a guide member (not shown), so that the block body 22 ismade movable only in the upper and lower directions without beinginclined. The swaying block body 22 is constantly urged downward by aspring, for example.

Accordingly, while the rotatable shaft 13 is rotating, as a result of acam mechanism that is made up of the flat plate cam 21 and the swayingblock body 22, a function of guiding the penetrating bar 23 along theinclined groove 22 b and so forth, the holding finger 40, which isprovided to project from the clamp base 24, alternately repeats a stateof clamping the workpiece with its distance to the opposing holdingfinger 40 reduced, and a state of unclamping the workpiece with itsdistance to the opposing holding finger 40 increased.

The swaying block body 22 is surrounded with the guide member, to beallowed to move only in the upper and lower directions. Alternatively,length of the flat plate cam 21 in the direction of the rotatable shaft13 may be increased not to limit a position of the swaying block body 22in the direction of the rotatable shaft 13.

The feed mechanism 30 includes a cylindrical groove cam 31 and a camfollower 32 a (see FIG. 5). The groove cam 31 is fixed to the rotatableshaft 13 to rotate in accordance with the rotary movement of therotatable shaft 13. The cam follower 32 a projects into a groove 31 aformed on an outer peripheral surface of the groove cam 31. The feedmechanism 30 includes a swaying rod 32, an operation rod 33, and afeeding bar 34 having an insertion hole 34 a. The rod 32 has asupporting point 32 b at a lower end portion of the rod 32. The rod 32is swayed in a shape of a circular arc with its supporting point 32 bserving as a center in accordance with the rotation of the cylindricalgroove cam 31. The rod 33 projects upward in FIG. 5 from an upper endportion of the swaying rod 32. The operation rod 33 is inserted in thehole 34 a such that the rod 33 is fitted into the hole 34 a with someplay.

A through hole 34 b is formed in the feeding bar 34. The above-describedclamp base 24 passes through the hole 34 b. The clamp base 24 is movableonly in upper and lower directions in FIG. 5 relative to the feeding bar34. Accordingly, while the rotatable shaft 13 is rotating, as a resultof a cam mechanism that is made up of the cylindrical groove cam 31 andthe swaying rod 32, an engagement relationship between the operation rod33 and the feeding bar 34, and so forth, an advancing operation to feedthe workpiece by making the holding finger 40, which is provided toproject from the clamp base 24, proceed rightward in FIG. 4 in thedirection of the rotatable shaft 13, and a returning operation to returnthe workpiece by making the holding finger 40 proceed leftward in FIG.4, are alternately repeated.

As a result of the combination of change of a distance from an shaftcenter of the shaft 13 to the outer peripheral surface of the flat platecam 21 fixed to the rotatable shaft 13, and position change of thegroove 31 a of the cylindrical groove cam 31 fixed to the rotatableshaft 13 in an axial direction of the shaft 13, the clamp-unclampoperation and the advance-return operation are synchronized. Morespecifically, as illustrated in FIG. 7, in accordance with thereciprocation of the upper die 3 in upper and lower directions, theoperation to advance the workpiece with the workpiece clamped (held) bythe holding finger 40, and the operation to return the workpiece withthe workpiece unclamped (released) from the holding finger 40 arealternately repeated.

FIGS. 8A to 8E illustrate states of a main feature of the transfermechanism 4 at time (A) to time (E) in the timing diagram in FIG. 7.

At time (A) in FIG. 7, as illustrated in FIG. 8A, the holding finger 40is advanced to a maximum extent toward a reverse side of a plane ofpaper, and holds the workpiece. When the upper die 3 makes thetransition to descend from its lifted position and time elapses fromtime (A) to time (B), because of functions of the rod 11, the crankmechanism 12, the cam mechanism of the feed mechanism 30 and so forth,which coordinate with the upper die 3, as illustrated in FIG. 8B, thefeeding bar 34 is made to proceed rightward, so that the holding finger40 is also made to proceed rightward, holding the workpiece.

Then, when the upper die 3 continues going down and time elapses fromtime (B) to time (C), the holding finger 40 is moved backward to amaximum extent from its maximum forward position toward an upper side ofthe plane of paper so as to release the workpiece, without changing theposition of the feeding bar 34 in rightward and leftward directions asillustrated in FIG. 8C, owing to functions of the rod 11, the crankmechanism 12, the cam mechanism of the clamping mechanism 20 and soforth in synchronization with the upper die 3.

When the upper die 3 makes the transition to be lifted up from itslowered position and time elapses from time (C) to time (E), asillustrated in FIG. 8E, the feeding bar 34 is made to proceed leftward,so that the holding finger 40 is also made to proceed leftward with theholding finger 40 located at its maximum backward position (with theworkpiece released), because of the functions of the rod 11, the crankmechanism 12, the cam mechanism of the feed mechanism 30 and so forth,which coordinate with the upper die 3. At time (D) (i.e., at a maximumlowered position or bottom dead point of the upper die 3) in the courseof the time between time (C) and time (E) when the upper die 3 makes thetransition to be lifted up from its lowered position, the workpiece ispressed between the lower die 2 and the upper die 3.

When the upper die 3 continues being lifted up and time elapses fromtime (E) to time (A), owing to functions of the rod 11, the crankmechanism 12, the cam mechanism of the clamping mechanism 20 and soforth in synchronization with the upper die 3, as illustrated in FIG.8A, without changing the position of the feeding bar 34 in rightward andleftward directions, the holding finger 40 is advanced to a maximumextent from its maximum backward position toward the reverse side of theplane of paper, so as to hold the workpiece.

As a result of the above-described configuration and operation of thedie 1, in the transfer mechanism 4 of the die 1, the rod 11 is engagedwith the upper die 3, so that the rod 11 is synchronized with thereciprocation of the upper die 3 in upper and lower directions. Thereciprocation of the rod 11 is converted into the rotary movement of therotatable shaft 13 in the crank mechanism 12. The rotary movement of therotatable shaft 13 is converted in the clamping mechanism 20 into theoperation of clamping-unclamping of the workpiece by the holding finger40, and the rotary movement of the rotatable shaft 13 is also convertedin the feed mechanism 30 into the operation to advance the holdingfinger 40 in a work transfer direction and to return the holding finger40 in a counter-work transfer direction, i.e., into the advance-returnoperation (the holding finger 40 advances the workpiece in a directionthat crosses the reciprocation direction of the upper die 3, and theholding finger 40 is returned after the advancement of the workpiece).

Accordingly, when the workpiece is pressed between the lower and upperdies 2, 3 of the die 1, the workpiece is transferred by the transfermechanism 4 in synchronization with the reciprocation of the upper die3. As above, press working operation and transferring operation arereadily synchronized only by attaching the die 1 to the press machinewithout adapting the press machine.

As illustrated in FIG. 10, conventionally, when a die 101 is mounted ona press machine, in order to transmit power to a transfer mechanism 104,for instance, a rotatable shaft of the press machine (i.e., a positioncorresponding to a base end of a black arrow) needs to be adapted foroutput power. Even if a transfer mechanism having an actuator, which isprovided separately from the press machine, is employed, for the sake ofthe synchronization between press working operation and transferringoperation, the press machine needs to be adapted for the installation ofa sensor for detecting an operating position of the press machine at theposition of the press machine corresponding to the base end of the blackarrow.

On the other hand, when the die 1 of the present embodiment is employed,as illustrated in FIG. 9, the transfer mechanism 4 is operated in thedie 1 by means of a part of power of the press machine to operate thedie 1.

Moreover, both the clamping mechanism 20 and the feed mechanism 30convert the rotary movement of the rotatable shaft 13 into theclamp-unclamp operation and the advance-return operation of the holdingfinger 40 using their cam mechanisms. Therefore, the conversion ofoperation of the rotatable shaft 13 is made very easy.

The embodiment of the invention have been described above. However, theinvention is not by any means limited to the above-described embodiment,and may be embodied through various modifications without departing fromthe scope of the invention.

Modifications of the above embodiment will be described below. In theabove embodiment, the die 1 includes the lower die 2 and the upper die3. Alternatively, the die 1 may be any die as long as it is a die thatis made up of a stationary die and a movable die and that performsplastic deformation work on a workpiece between the stationary die andmovable die. For example, the die 1 may be a die in which a movable diereciprocates in a horizontal direction to change an opposing distancebetween the movable die and a stationary die.

In the above embodiment, the flat plate cam 21 is used in the clampingmechanism 20, and the cylindrical groove cam 31 is employed in the feedmechanism 30. However, the cams of the cam mechanisms are not limited tothe flat plate cam 21 and the cylindrical groove cam 31. For both theclamping mechanism 20 and the feed mechanism 30, for example, in thecase of a plane cam, a plate cam, groove cam, rib cam, or conjugate cammay be used, and in the case of a solid cam, an end cam, cylindricalgroove cam, cylindrical rib cam, or drum-shaped rib cam may be employed.

In the above embodiment, both the clamping mechanism 20 and the feedmechanism 30 include the cam mechanisms. However, the mechanisms 20, 30are not limited to those having the cam mechanisms. One or both of themechanisms 20, 30 may be a link mechanism that does not have a cammechanism. Furthermore, a link mechanism without the crank mechanism 12may be used for the conversion of the reciprocation of the rod 11. Forexample, a rack and pinion gear may be employed for the conversion ofthe reciprocation.

In the above embodiment, the transfer mechanism 4 transfers theworkpiece in the horizontal direction, which is perpendicular to adirection of the reciprocation of the upper die 3. However, the transfermechanism 4 is not limited to those which transfer the workpiece in thehorizontal direction. The transfer mechanism 4 may be any mechanism aslong as it is a mechanism which transfers the workpiece in a directionthat crosses a direction of the reciprocation of the movable die. Inaddition, the transfer mechanism 4 may be a mechanism that performs thecombination of the transfer of the workpiece in the direction thatcrosses the direction of the reciprocation of the movable die, and thetransfer of the workpiece in the reciprocation direction.

In the above embodiment, the workpiece is pressed between the lower andupper dies 2, 3 of the die 1. However, the embodiment is not limited tothis as long as it is that which performs plastic deformation work on aworkpiece between the stationary die and movable die. For example, theinvention may be effectively applied to a die for forge processing.

Additional advantages and modifications will readily occur to thoseskilled in the art. The invention in its broader terms is therefore notlimited to the specific details, representative apparatus, andillustrative examples shown and described.

1. A die for performing plastic deformation work upon a workpiece, thedie comprising: a stationary die; a movable die that is opposed to thestationary die and reciprocatable in a first direction to change adistance between the stationary die and the movable die; and a transfermechanism that is configured to transfer the workpiece, upon which theplastic deformation work is performed between the stationary die and themovable die, in a second direction that crosses the first direction,wherein the transfer mechanism includes: a clamp portion that is adaptedto clamp and unclamp the workpiece; a synchronizing member that isengaged with the movable die to reciprocate in synchronization withreciprocal movement of the movable die; a clamp-unclamp operationconverter that is configured to convert reciprocal movement of thesynchronizing member into clamping and unclamping of the workpiece bythe clamp portion; and an advance-return operation converter that isconfigured to convert the reciprocal movement of the synchronizingmember into advance-return operation of the clamp portion, whereby theclamp portion advances the workpiece in the second direction and isreturned after advancement of the workpiece.
 2. The die according toclaim 1, wherein: the transfer mechanism further includes a rotatableshaft and a crank mechanism that is configured to convert the reciprocalmovement of the synchronizing member into rotation of the rotatableshaft; the clamp-unclamp operation converter is configured to convertthe rotation of the rotatable shaft into the clamping and unclamping ofthe workpiece by the clamp portion; and the advance-return operationconverter is configured to convert the rotation of the rotatable shaftinto the advance-return operation of the clamp portion.
 3. The dieaccording to claim 2, wherein the clamp-unclamp operation converterincludes a cam mechanism that is configured to convert the rotation ofthe rotatable shaft into the clamping and unclamping of the workpiece bythe clamp portion.
 4. The die according to claim 2, wherein theadvance-return operation converter includes a cam mechanism that isconfigured to convert the rotation of the rotatable shaft into theadvance-return operation of the clamp portion.